Off Grid Home › Forums › Technical Discussion › 12V Refrigerator
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May 21, 2008 at 12:00 AM #62435kabir424Participant
I am going to be moving off-the-grid near the end of July of this year and I really wouldn’t mind having some sort of refrigeration for a little soy milk, cream cheese, etc. I plan to use a couple of 200 amp/hr deep cycle batteries and have about 300 watts of solar power. Is this a feasible option here or do I need something more efficient like a SunDanzer?
https://www.coolerdirect.com/engel-12v-cooler-12-volt-freezer-3869-prd1.htm
May 22, 2008 at 12:00 AM #63941JustmeParticipantHi,
Just remember you should not over drain the batteries. 2 x 200 amp/h bats will give you just 80amp/h at the reccomemnded 20% DOD (depth of discharge) to give you the max battery life. Going to 50% DOD will half the bat life, going to 80% DOD will reduce batt life to a fraction of the 20% DOD time.
That 80amp/h will give you 960watts. How many watts is the 12v fridge? Divide the 960w by the about a 1/3rd of the fridge watts (as it wont be drawing power all the time).
Fully charged bats read 12.6v
discharge by 20% & the will read about 12.3v
discharge by 40% & the will read about 12.2v
discharge by 60% & the will read about 11.9v
discharge by 80% & the will read about 11.6v
discharge by 100% & the will read about 10.6v
So you can see that the inverter cut off points set normaly at 10.5v is far to low.
300w of solar panel “should” give you upto 1380 watts during the height of summer but only 3-400 watts in winter. (in the UK)
Justme
May 28, 2008 at 12:00 AM #63944oystercatcherMemberI have a sundanzer freezer model which is running off an amateur
radio power supply. If the power goes out I switch it to batteries.
When I first started the unit it drew power continously for over
May 28, 2008 at 12:00 AM #63945oystercatcherMemberI have a sundanzer freezer model which is running off an amateur
radio power supply. If the power goes out I switch it to batteries.
When I first started the unit it drew power continuously for over
12 hours probably longer so you need to factor that in. It drained
an 80 amp hour battery to 50% and was still not at nominal temp.
Once it is up and running it uses between 4 and 6 amps for
15 to 20 min per hour depending on your settings and the amount
of food stored.
For start up you could probably put a lot of ice inside to get
it to cool down.
There are conversion kits to modify a freezer to a refrig and
vice versa but I really wish I could just flick a switch.
The unit is quite lighweight and when empty is easily manhandled
by one person although lifting is not likely.
I have two 75 watt solar panels which will eventually be hooked up.
September 18, 2008 at 12:00 AM #64070lamar5292ParticipantIf that is all the food you are storing go to wal mart and look at the 12 volt fridges in the sporting good section made by coleman. These work good and use only about 25 watts.
You can see my website for ideas:
https://www.freewebs.com/simplesolarhomesteading
LaMar
February 17, 2010 at 12:00 AM #64439 -
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